JPH0554444A - Magnetic field modulation type magneto-optical disk - Google Patents

Abstract

PURPOSE:To protect a magnetic head and a magnetic field modulation type magneto-optical disk from the spark of static electricity charged on the magnetic field modulation type magneto-optical disk and to prevent damage from it. CONSTITUTION:On a round substrate 1 provided with a center hole for the positioning of a spindle, an information recording film 2 by which information is recorded optically or magneto-optically is formed; and in order to protect this information recording film 2 from damage, etc., from external cause, a protective film 3 to cover the information recording film 2 is provided. A conductive protective film 3 in which an electrically conductive material is mixed is used as the protective film 3, a static electricity charged on the magneto- optical disk is guided to the magneto-optical disk device and the damage to the magnetic head 6 and the magneto-optical disk caused by the spark of the static electricity is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical disk, and more particularly to a magnetic field modulation type magneto-optical disk which records information by reversing a magnetic field at high speed.

[0002]

2. Description of the Related Art Conventionally, a magnetic field modulation type magneto-optical disk of this type is used by being mounted in a magnetic field modulation type magneto-optical disk apparatus, and when mounted in the magnetic field modulation type magneto-optical disk apparatus, the magnetic field modulation type magnetic disk is used. Of an objective lens arranged on the opposite side of the substrate of the magneto-optical disc from the information recording film formed on the substrate, and a magnetic head arranged on the same side of the substrate as the information recording film. The intensity of light from the recording / reproducing light source, which is held between the objective lenses, and the direction perpendicular to the substrate generated by the recording / erasing magnetic field generating coil provided in the magnetic head. The information recording film for storing information by utilizing the reversal of the magnetic field and the protective film formed so as to cover the information recording film.

[0003]

In the magnetic field modulation type magneto-optical disk device having the above-mentioned structure, the magnetic head reverses the magnetic field having the magnetic field strength necessary for recording and erasing information at a speed of several MHz. In order to do so, it is inevitably arranged at a position of a distance of several tens μm to several hundreds μm from the information recording film.

In the conventional magnetic field modulation type magneto-optical disk, static electricity is charged on the protective film enclosing the information recording film and the entire magneto-optical disk due to friction with air due to rotation and the like. In order to keep the distance between the information recording film and the magnetic head short, the protective film cannot have a thickness of several tens μm to several hundreds μm or more. Since the distance of the protective film is short, static electricity charged in the magneto-optical disk is sparked between the magnetic head and the magneto-optical disk, resulting in damage to the information recording film and the magnetic head. ..

It is an object of the present invention to provide a magnetic field modulation type magneto-optical disk in which static electricity charged in a magnetic head is sparked to prevent damage.

[0006]

In order to achieve the above object, in a magnetic field modulation type magneto-optical disk according to the present invention, light emitted from a recording / reproducing light source is condensed on an information recording film of the magneto-optical disk by an objective lens. Then, the information is recorded on the information recording film on the substrate by using the magnetic field generated by the recording / erasing magnetic field generating coil of the magneto-optical head arranged on the side facing the objective lens with the magneto-optical disk sandwiched therebetween. ，
A magnetic field modulation type magneto-optical disk used for a magnetic field modulation type magneto-optical information recording / reproducing apparatus for erasing and reproducing, wherein an information recording film formed on a substrate has a protective film encapsulating the same. Is a conductive protective film mixed with a conductive material.

Further, the conductive material is a non-magnetic material.

[0008]

The static electricity charged on the magneto-optical disk is released to the magneto-optical disk device to prevent the magnetic head and the magneto-optical disk from being damaged by the spark of static electricity.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the magnetic field modulation type magneto-optical disk of the present invention is formed of three layers of 1-3.

That is, a circular substrate 1 made of glass or plastic having a central hole 8 provided for positioning the spindle for rotating the magnetic field modulation type magneto-optical disk, and optically or magneto-optically. An information recording film 2 necessary for recording and reproducing information, and a protective film 3 encapsulating the information recording film 2 to prevent the information recording film 2 from being damaged or corroded by an external factor. It is a layer.

The information recording film 2 is formed on the substrate 1, and the protective film 3 is formed so as to cover the information recording film 2.
A finely divided conductive material is mixed in the protective film 3, so that the conductive protective film 3 having a low electric resistance is formed.

As shown in FIG. 2, the magnetic field modulation type magneto-optical disk has an objective lens of an optical head disposed on the side opposite to the information recording film 2 with respect to the substrate 1 when mounted in an optical disk device. 4 and a magnetic head 6 arranged on the same side of the substrate 1 as the information recording film 2 and rotated, and focused on the information recording film 2 by the objective lens 4. The information recording film 2 is formed by utilizing a focused light 5 of light from a recording / reproducing light source (not shown) and a magnetic field 7 generated by the magnetic head 6 in a direction perpendicular to the substrate 1.
Information is recorded and played back.

Here, the magnetic field 7 having the strength required for recording / erasing is used.
The distance between the magneto-optical disk 7 and the magnetic head 6 is maintained at about several tens of μm to several hundreds of μm in order to invert at a high speed of about several MHz. It is formed on the information recording film 2 and has a surface electric resistance of 1 × 1.
By setting the resistance to about 0 ⁶ Ω / cm, static electricity generated on the magneto-optical disk due to friction between the rotating magneto-optical disk and air can be eliminated through a grounding mechanism provided in the magneto-optical disk device. Therefore, it is possible to prevent the static electricity from being sparked between the magnetic head 6 and the magneto-optical disk, which are at a short distance as described above. Therefore, this spark prevents the magnetic head 6 and the information recording. It is possible to prevent the membrane 2 and the substrate 1 from being damaged.

Further, when a magnetic material such as iron is used as the conductive material mixed in the conductive protective film 3, the magnetic field 7 in the direction perpendicular to the substrate 1 is affected and the information recording film is formed. Although the magnetic field strength on the film surface of No. 2 is small and the direction of the magnetic field is changed, a non-magnetic and conductive material such as aluminum is used as a material mixed in the conductive protection film 3. The influence on the magnetic field 7 can be eliminated.

[0016]

As described above, by forming the conductive protective film on the magnetic field modulation type magneto-optical disk, the magnetic head and the magneto-optical disk are effectively protected from the influence of static electricity charged on the magneto-optical disk. The effects are that stable recording / reproduction and reliable guarantee of recorded information can be performed.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a magnetic field modulation type magneto-optical disk of the present invention.

FIG. 2 is a diagram showing an example of mounting a magneto-optical disk in a magneto-optical disk device.

[Explanation of symbols]

 1 Substrate 2 Information Recording Film 3 Conductive Protective Film 4 Objective Lens 5 Focused Light 6 Magnetic Head 7 Magnetic Field

Claims (2)

[Claims] 1. A magneto-optical head arranged on the side opposite to the objective lens with the light emitted from a recording / reproducing light source being condensed on an information recording film of a magneto-optical disc by an objective lens and sandwiching the magneto-optical disc. Magnetic field modulation type magneto-optical disk for use in a magnetic field modulation type magneto-optical information recording / reproducing apparatus for recording, erasing and reproducing information on an information recording film on a substrate by utilizing a magnetic field generated by the recording / erasing magnetic field generating coil The information recording film formed on the substrate has a protective film encapsulating the information recording film, and the protective film is a conductive protective film mixed with a conductive material. Type magneto-optical disk. 2. The magnetic field modulation type magneto-optical disk according to claim 1, wherein the conductive material is a non-magnetic material.